Boom extension arm



FIG. 1 is a perspective view of a boom extension arm in accordance with the present invention;

FIG. 2 is a right side elevational view of the boom extension arm of FIG. 1, the left side elevational view being a mirror image of the right side;

FIG. 3 is a front elevational view of the boom extension arm of FIG. 1;

FIG. 4 is a rear elevational view of the boom extension arm of FIG. 1;

FIG. 5 is a top plan view of the boom extension arm of FIG. 1; and,

FIG. 6 is a bottom plan view of the boom extension arm of FIG. 1.

The broken line showing of portions of the design and of environment forms no part of the claimed design. 

The ornamental design for a boom extension arm, as shown and described. 